CSS-自定义虚线

<div class="line"></div>

.line::after{
content: "";
    display: block;
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(to right, #e0e0e0, #e0e0e0 10px, transparent 10px, transparent);
    background-size: 21px 100%;
}

效果：